necessarily /ˈnesisərili/ adv. 当然；必然：Rich people are not necessarily happy. 有钱人不一定都很幸福。Good-looking food doesn’t necessarily taste good. 中看的食品不一定有好味道。 The study of a foreign language is necessarily difficult. 学习一门外语当然不易。
necessary /ˈnesisəri/ I. adj. 1. 必需的，必要的：Food is necessary to life.食物是生命所必需的。 It is necessary that he (should) do so. 他必须这样做。2.必然的，不可避免的：Death is the necessary end of life. 死是生命的必然终结。This is a necessary conclusion.这是个必然的结论。‖II. n. 必需品(多用 pl.)：He has nothing around him but the simplest necessaries. 除了简单的必需品，他什么都没有。
［辨析］见inevitable
